What does the label "exp" stand for on a guitar effect pedal? Example: there is a delay/reverb pedal with various controls - rate, repeat, tone, etc. One of the knobs is labelled "exp." Thanks for any response, Jeff

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    Exp typically means expression in effects, although what expression does is heavily dependent on the exact module. Can you link an example?
    – Dom
    Dec 28, 2016 at 19:06
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    which pedal in particular? Dec 28, 2016 at 21:02
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    expression is usually a rocker pedal like what you see on a wah or volume pedal. Perhaps the "Exp" refers to a tip-ring-sleeve midi connector.
    – Yorik
    Dec 28, 2016 at 22:45

1 Answer 1


In guitar pedal lingo - "EXP" usually means expression as in "expression pedal" which can be used to control effects such as a wha wha but are also used by guitarist to facilitate real time control of almost any variable such as volume, tone, echo repeats, delay time and many other variables.

If your pedal has a control knob labeled "EXP" then most likely it also has an expression pedal input to allow the use of an expression pedal to control some of the parameters in a live music setting while using both hands to play the guitar.

For example the EarthQuaker Devices Avalanche Run Stereo Delay and Reverb Pedal has a knob that allows you to specify which of the parameters you want to control with an expression pedal. The knob is labeled EXP on this pedal.


With this particular delay/reverb pedal the EXP control knob would be used if you plugged an expression pedal into the input on the side (also labeled EXP). Then the knob would allow you to select the specific parameter (decay, delay time, repeats, etc).

If your pedal also has an input for a separate expression pedal, I am sure the EXP control knob is there to work in conjunction with your separate expression pedal.

  • perfect. and it so happens that the avalanche run is the pedal i have. this explains it. thanks for taking the time to post this. so cool that there are people willing to share their knowledge.
    – Jeff
    Jan 20, 2017 at 1:55
  • You are welcome. Glad I could help. You can mark this as an accepted answer if you want. I think you get rep points when you mark an answer to your question as accepted. Jan 22, 2017 at 0:03

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